Understanding dependencies

The modifier stack, just as the name implies, is sort of a layers basedinterface, in which you are able to stack modifiers on top of one another.However, you need to understand that the order in which they are placed in thestack is of paramount importance.It's not important what chronological order you add them in.What matters at the end is, what is the structure of the modifier stack?How are they layered on top of one another?Currently I have got a box with a bend, but as you remember from our originalmodel that I showed at the beginning, we also want this to twist.

So this is a good illustration of how dependencies work.If I add a Twist modifier currently, and I have got the Bend modifier selected,it's going to place the Twist above the Bend.So, I am going to scroll way down here looking for Twist. Here it is.You will notice that it's placed the Twist above the Bend in the stack.If I adjust the Twist Angle now, you will see we will get an undesirable result.I mean that might be good in some experimental abstract art sense, but that'snot the form that we are trying to achieve.

What we are trying to get is a box that was twisted and then bent over after.So the order of the modifiers in the stack is critical here.I could do a couple of things.I could delete the twist and re-add it, or I could just drag and drop it.So if I wanted to delete it, I would just select it and click Remove.And if I want to make sure that that Twist appears before the Bend, I can selectthe Box, and that's the current level I have got selected.And when I add the Twist, it will be added above the Box, but below the Bend.

So go back down to Twist, and now we are getting something closer to what weare trying to achieve.Additionally, you can drag and drop modifiers in the stack to change their order.So just click on it, hold the mouse and drag, and you will see a blue line thatwill indicate where you are going to place it.So when I release the mouse then, now the Twist is above the Bend.I can hold down the mouse button again and drag it back down where it was.And that's a better structure to this particular shape.

So that's a dependency.The modifier stack has dependencies.In other words, one thing depends on another and it flows in a linear, logical fashion.And if it's not doing what you think it should be doing or what you want it tobe doing, maybe you need to reevaluate whether you have got the correctstructure to the stack or not.Additionally, by the way, don't forget you can always turn these on and off atwill in order to see what's going on.So I can turn the Bend off and now I can see what's happening with the Twist.

So let's say, for example, I wanted the Twist to start not at the bottom at thebase, but somewhere up a little bit higher.I might go into Gizmo mode for the Twist modifier and move that Gizmo up alittle bit, and then also turn on Limits.So turn on the Limit and increase the Upper Limit. I might want to increase this a lot.I don't know how much I want here, but maybe I will make it 18 feet.I am going to make this bigger by hitting Alt+W, so you can kind of see what weare up against here.By the way, if things get confusing to you because of the selection brackets,you might want to turn those brackets off.

That's the J key on your keyboard.I tend to turn them off when I am working on a single model.So I can move my Twist Gizmo up and down, and you can see it's only twisting a certain area.It's not twisting anything below here or above here, because I have moved theGizmo and I have assigned an Upper Limit.So that was pretty good.I can turn my Bend back on and see what I have got.That's pretty close.I could play around with things like the Angle.Let's say I want this Angle to be 360 degrees. Press Tab.

You will note that although it may be twisting 360 degrees, this is notnecessarily landing where we want it to be.You can see how, okay, on this side it's square relative to the grid, butin this side it's not.And we are going to have to just sort of play around with this a little bitby adjusting the position of the Gizmo and/or the Limits until it kind oflines up the way we want.So I will probably want to go into an ortho view, Alt+W. Look at this in theFront view, and kind of tweak out on this a little bit until it kind of linesup where I want it.

And the thing about this though is that every one of these thingsaffects everything else.So if I want a greater angle, let's say I wanted 720 degrees here.We got lucky there because that was an exact multiple, but if I had chosensomething that wasn't an exact multiple, like oh, I want 460 degrees orsomething like that, then that means I would have to go in and play aroundwith these once again. So 720 was good.And once again, Alt+W, looking in the Front view until that lines up, so itlooks like it's square to the world.

And I am just trying to finish this up with a little bit of symmetry so that itlooks like it's the same on all sides.And that's how we work with dependencies in the modifier stack.